Requesting Input
Mathematica usually works by taking whatever input you give, and then processing it. Sometimes, however, you may want to have a program you write explicitly request more input. You can do this using Input and InputString.
| Input[] | read an expression as input |
| InputString[] | read a string as input |
| Input["prompt"] | issue a prompt, then read an expression |
| InputString["prompt"] | issue a prompt, then read a string |
Exactly how Input and InputString work depends on the computer system and Mathematica interface you are using. With a text-based interface, they typically just wait for standard input, terminated with a newline. With a notebook interface, however, they typically get the front end to put up a "dialog box", in which the user can enter input.
In general, Input is intended for reading complete Mathematica expressions. InputString, on the other hand, is for reading arbitrary strings.
